Air indicating and regulating apparatus for furnaces



Aug. 30, 1927.

R.' L. BLANCHARD AIR INDICATING AND REGULATING, APIARAVTUS FOR FURNACES Filed Jun 15, 1925 2 Sheets-Sheetv 1 M jl. l M/ II` A ATTORNEY 30 192 l Aug 7 R. L. BLANCHARD.

AIRINDICATING AND REGULATING APPARATUS FOR FURNACES beets-Sheet 2 fo Z Z ,7//f/////////. 5 3 l@ 2 f/ w 4 d 3. l nv n 7 Tu. a, d e l .l F

Patented Aug. y30, 1927.

UNI-TED `STATES 1,640,9zi PATENT ovarica.l

ROBERT L. BLANCHARD, OF NEW YORK, N. Y.

AIR INDIICATING AND REGULATING APPARATUS FOR FURNACES.

Application lediune i3, 1325. Serial No. 36,926.

provide a means whereby the proper amount.

of air maybe introduced over the fire.

Another object of the invent-ion is to provide an indicator which shows the direction f of flow of air thru the furnace-door into the furnace. f y

In the Abest embodiment of the invention, the draft indicator is mounted onA the outside of the door and an air preheater and retarder is mounted on the inside of the door, the draft indicator providingsubstantially no retardation to the air iiow but indicating the amount of such flow thru the air preheater and retarder.

- In accordance with the invention, the adjuster valve is provided with a scale and the number of revolutions per minute of the` indicator is noted for any givenrate area and position of the valve, so that with a certain number of revolutions per minute of the indicator for a given grate area, the amount of air passing by the indicator and over the fuel bed, is indicated. The Yactual amount or volume of air sosupplied may be determined by a suitable measuring instrument and is aso known from `practical eX- pei'ience. The draft indicator may thus be calibrated.

With the above and other objects in view, my invention consists in the parts, improvements and combinations more fully pointed out hereinafter.

Turning now' to the drawings, which illus-l trate one embodiment of the invention:

Figure 1, is a iront elevation, showing the draft indicator secured to the furnace door.

Figure 2, is a longitudinal section on linev Figure 6, is an enlarged vertical 'sectional view, showing the revolving vanes of the indicator.

n'igure 7, shows the air opening into the air preheater and retarder, and I Figure 8, is an elevation partly in section, of another form of indicator.

ln the drawings, the furnace door 10, which closes the fuel opening of the furnace,

is hinged at 11, and is provided with a door ycatch 12, and handle 13, and is mounted on the frame 1st, of the furnace, which has a grate 15, and vdamper 16. The door tightly fits the frame and is sealed to prevent air leakage. The door is provided with a main air draft, which, in the preferred eiiibodiment of the invention, takes the form of an air-draft opening 17, which may be opened more or less, or closed by a damper 18, pivoted at 19, upon the door. Thru this main draft 'substantially all .the air is supplied to the portion of theJ furnace behind the door.

In the best embodiment of the invention, an air. preheating, air-retarding and airdistribution chamber 20, is secured to the inside of the door by bolts 21, which pass thru ears 21EL of the chamber, the air chamvber being provided with an inlet opening 20a, a reservoir 22, and channels 23, formed by transverse partitions 24, communicating in series with each other (see Brunner Patent No'. 1,433,601, of October31, 1922). The air entering thru draft opening 17, passes into opening 2Oa and reservoir 22, and then back and forth along the stretch of passageways in series, in a serpentine path, finally discharging over the fuel bed thru openings 25. VThis introduces a draft resistance to the air and permits its -preheating so that the draft over the fuel bed and' the draft from beneath the fuel bed are balanced and equalized, and distributes the "air over the fuel bed. Accordingly one-half of the air for complete combustion is supplied thru the grate, the other half being supplied over the fuel bed. The draft is regulated by damper 16.

Turning lnow to the air-draft indicator, suitable means are provided suoli as an air vane, vfor indicating vthe flow of air thru the opening in the furnace door, means being also provided for securing the air vane into air-draft relation with the opening. The form of air vane may be varied. In the embodiment of the invention illustrated in Figures 2 and 6, a rotary vane is utilized.

iio i vide an air chamberV As illustrated, a plurality ot floating air vanes 26 (whose inclination determines their speed ot rotation), are mounted upon a carrier 27, the carrier resting upon a supporting pin 28. An elbow pipe having two arms 29 and 30, is provided, tue supporting pin for the air vanes being mounted on a vertical axis 'n the distant arm and the other arm being provided with means tor securing the pipe to the 'furnace door. Means are thus provided for securin(y the air vanes into air draft relation with the opening in the furnace door. The supporting pin 2S, is removably mounted on and carried by a traverse piec 3 which is fixed in one arm otl the elbow. ts inward proliection is limited by a stop, such strap A cap 32, provided with air openings 33, iter directing the air to the vane, is mounted upon the elbow arm, being preterably pivoted at 3d, and carrying a bail 35, which can be pushed under the lug 36, to clamp the cap down in piace. 'Vheii the cap is swung up, the vanes may be removed. ln the *form or the invention illustrated, the means tor securing the elbow pipe to the 'lfurnace door, includes a plate 37, upon which the elbow pipe is mounted. The plate carries a short tube 38, preferably cast integral with it, over which tlv arm 30 of the elbow is slipped. .The joint 89, prevents leakage. the latter passing behind the crosspiece 4t2, onthe plate 37, locks the elbow on the plate, the bolt passing thru an arm ot the elbow and carrying a thumb nut Means are provided for securing the plate 37, to the door. As illustrated, the bolts 21, which secure the air chamber 2O to the inside ot the door, serve to secure the plate to the outside ot the door', the bolts carrying nuts rlhe plate 3T, is provided with a rim jointl 45, which seals the plate and prevents leal;- age, the rim being bentso as to separate the plate from. the iurnace door and pro- 'lhis air chamber is in registering relation with the opening 17, in the door.

In the term of air vane indicator shown in Figure 8, the elbow pipe arm 100, carries a pivoted vane 101, which may extend hori-V zontally across the interior ot the pipe and is counterbalanced by adjustable weight 102 and is held in vane closing position by coiled spring 103. lt is shown deflected by the passage of air. rllwo scales 104i-, 105, show the displacement ot the vane on opposite sides ot closing position, scale 104, showing the effect due to the incoming` air .and Ascale 105, showing the reverse action when gas is generated, by closed dampers, rin the tuel bed and streams outwardly thru the pipe.

ln accordance with the invention the volume et air passing over tle fuel bed is A bolt e0, having a head all.,

Ano substantial increased vresistance to measured and determined and the amount of air so'supplied is controlled until a pre- Y position. rlhe air regulating means includes j a valve 4&7, which in the best embodiment oli` zhe invention, is mounted on the plate o This valve is preferably-a slide valve provided with a handle 48, and slot e9, which lits over bolt 40. @The valve is provided with a numbered scale and variesY the opeiiolf the ports 50 in the plate 37. n

lhe cross-section ot the elbow pipe Awhen reduced by the space talen up by .the air vanes and their support, is greaterj than that ci' the ports controlled by the slide valve and the area of the opening 17, in the tui-nace door is greater than the cross-sec'- tion olf the elbbw pipe, the area of the inlet ogening 20", into the heating and retardi-ng chamber 20, being less than the cross-sec;- tion of the elbow pipe and less than the area ot the air openings in the cap. lnr this vay, the elbow pipe audits air vanes offer passage ot the air thru the air chamber 20, and the slide valve can serve as a regulating valve when desired. i

The valve or adjuster' slide beingprovided with a numbered scale and observations ot the revolutions per minute of the indicator vane for any given grate area being the noted, this will enable a. tableo't standards to be prepared. For a delinite grate area, and a specified kind oli coal, there should be a specilied amount ot' air delivered over the lire and a Vcertain number of revolutions per minute ot the indicator vane will indicate this condition. 'The adjuster' slidercaii be regulated until this desired condition is obtained and toi' deiinite grate areas it will be found that the adjuster' slide will assume dilliereiit positions which byreason of the numbered scale thereon, can be Vrecorded and the table of standards for definite grate areas thereby established. At the saine time,-by means of a suitable measuring instrument or trom practical experience, the amount or volunine ot air supplied thru the elbow pipe may be ascertained.

' l/lhile the above can be accomplished with but one size ot vane vand inlet pipe, the 'construction ot this table ot standards 'will be simplified by the use ot' two or more sizes Vnormal condition, the indicator vane did not indicate a normal number of revolutions per minute,l the increase or decrease from normal would indicate the adjustment required. lf the number of revolutions per minute is `above normal, proper regulation of dampers could be determined and if with the dampers closed the vane still revolved defective damper conditions would at once be indicated and the remedy could be effected as the case might require. lVhen drafts are reduced for purposes of holding fires as for night runs, if the vane comes to a standstill and then reverses, ruiming in counterclockwise direction, this serves to indicate a too severe checking of the draft and the back flow' of coal gas into the cellar and building. The slight adjustment of dampers until t e vane stops or revolves slowing in clockwise direction insures safety and the carrying out by the stack of the gases generated.

With particular reference to supplying about one-half-the total air above the grate and the other half through the fuel bed, it is to be noted that the installation of a vane of the same size carried on an inlet pipe of the same size, mounted on the ashpit door, as shown in Figure 3, will permit of positive adjustment since with the adjuster slide on the vane connected with the pipe introducing air over the fire,v adjustment can be made rendering the number of revolutions per minute of both vanes the same and hence` the volume of air introduced over and under the fire, the same. Any variation of these percentages which specic coal or furnace conditions might warrant could likewise be readily obtained.

t will thus be observed that the indicator vane provides a permanent means for indicating draft and furnace conditions and any variations from normal can at once be noted and repairsA made which" defects if they develop without this means of calling attention thereto, might continue for an indefinite period to the disadvantage and lack of economy to the owner.

Having thus described the invention and its construction and operation, it will be understood that changes may be made in carrying the invention into effect without departing from the principle thereof.

Vhat I claim is:

- 1.'A draft indicating device for furnaces, which shows the direction of flow. of air thru the furnace door into the furnace, coinprising in combination with a furnace door having a main air draft opening thru which substantially all the air is supplied to the portion of the furnace behind the door, a pipe projecting from the furnace door, an air Avane mounted in the projecting portion of said pipe, thereby bringing said air vane into air draft relation with said opening in' the furnace door.

2. vA draft indicating devicefor furnaces comprising in combination with the furnace having a combustion chamber providecL with a main air draft, an elbow pipe projecting from the furnace, an air vane mounted in the distant arm of said pipe, on its vertical f aXis, and means for securing said pipe to said furnace so as to bring the pipe and the air vane mounted therein into air draft relation with the main airdraft of the coinbustion chamber of the furnace, the air vane thus indicating the direction of flow of air into the combustion chamber.

3. A draft indicating device for furnaces, which shows the direction of flow of air thru the furnace door into the furnace, compris- Y ing in combination with a furnace door having al main air draft opening, thru which substantially all the air is supplied to the portion of the furnace behind the door, a

projecting pipe, a floating, rotary air vane mounted in the projecting portion of said pipe, said air vane adapted to revolve in either direction, and means for securing said pipe to the furnace in draft relation to said main air draft opening.

41:. A draft indicating device for furnaces, which shows the direction of flow or air thru the furnace door into the furnace, comprising in combination with a furnace door having a main air draft opening, an air chamber provided with a serpentine, air-retarding pathmounted on the inside of the furnace door communicating with said main air draft opening, a floating air vane, an elbow pipe having two arms, means for securing the elbow pipe at the front of the said main air draft opening in the furnace door, and means for securing the air vane on a vertical aXis in the distant arm ofsaid elbow pipe.

5. A draft indicating device for furnaces, which shows the direction of fiow of air thru the furnace door into the furnace, comprising in combination with a furnace door having a main air draft opening thru which substantially all the air is supplied to the portion of the furnace behind the door, an air chamber mounted on the inside of the furnace door in communication with the main air draft opening, an elbow pipe having two arms, a rotatable air vane mounted vertically on the distant arm of said pipe, a plate on which the elbow pipe is mounted so r' and means for securing Said plate to said furnace door in a position separated there from eo as to provide 'an air chamber, thereby bringing' said air vane and air chamber into air drart relation with the said opening in the furnace door.

6. A draftindicating.;v device for furnaces, which shows the direction of flow of air thru the furnace door into the furnace, comprising in combination with the furnace door having` a main air draft opening, an elbow pipe mounted adjacent to and in draft relation with Said main draftopening in the distant arm of which pipe a floating air vane is mounted on a vertical axis, said arm provided with an air opening` admi ating air to the vane, a plate carrying;` said pipe and means for securing' said plate to and away from Said furnace door to form an air chamber between Said plate and door.

's'. A draft indicating device for furi'iaceea which Showe the direction of flow of ai r thru the furnace door into the furnace, comprising in combination with the furnace door l'iaving a main draft opening;7 an elbow pipe mounted adjacent 'to and in draft relation with Said main draftopening in the distant arm of which pipe an air vane is mounted,

said arm provided with air openings admittingl air to the vane, a piate carrying said pipe a bolt paseing; thru the other arm of said elbow for securing the elbow to Vsaid plate and ineansfor securing the plate to said furnace door, thereby brinoing said air vane into air-draft relation withthe said opening` in the furnace door. Y

8. A draft device which shows the direction of iiow of air thru a furnace door into a furnace, comprisingv in combination with the furnace door having a main draft opening', valve regulating means for controlling` the amount of air Supplied thru the Said opening in the furnace door above the fuel bed, av pipe carrying Said valve regulating;

means, in air-draft relation with the said RGBERT L. BLANCHARD 

